US5391450A - Toner image heat-fixing method - Google Patents

Toner image heat-fixing method Download PDF

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Publication number
US5391450A
US5391450A US08/232,340 US23234094A US5391450A US 5391450 A US5391450 A US 5391450A US 23234094 A US23234094 A US 23234094A US 5391450 A US5391450 A US 5391450A
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Prior art keywords
toner
fixing roller
fixing
roller
weight
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US08/232,340
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Takayuki Nagatsuka
Tatsuya Nakamura
Hiromi Mori
Takaaki Kohtaki
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Canon Inc
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Canon Inc
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/0802—Preparation methods
    • G03G9/0804—Preparation methods whereby the components are brought together in a liquid dispersing medium
    • G03G9/0806—Preparation methods whereby the components are brought together in a liquid dispersing medium whereby chemical synthesis of at least one of the toner components takes place
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/20—Fixing, e.g. by using heat
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08775—Natural macromolecular compounds or derivatives thereof
    • G03G9/08782—Waxes
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
    • G03G9/08795—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/087—Binders for toner particles
    • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
    • G03G9/08797—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775 characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature

Definitions

  • the present invention relates to a method for the heat-pressure fixing of a toner image to a transfer medium such as plain paper or an overhead projector (OHP) film.
  • a transfer medium such as plain paper or an overhead projector (OHP) film.
  • a number of methods are hitherto known as electrophotography as disclosed in U.S. Pat. No. 2,297,691, etc.
  • copies are obtained by forming an electrostatic latent image on a photosensitive member by various means utilizing a photoconductive material, developing the latent image by the use of a toner, and transferring the toner image to a transfer medium such as paper if necessary, followed by fixation with heat, pressure, heat-and-pressure, or solvent vapor.
  • Methods for development using toners or methods of fixing toner images have been hitherto proposed in variety, and methods suited for any respective image-forming processes have been employed.
  • toners As methods of producing toners, it is commonly known to use a process comprising melt-kneading a thermoplastic resin, a coloring agent such as a dye or a pigment and additives such as a charge control agent to effect their uniform dispersion, thereafter cooling the melt-kneaded product, pulverizing the cooled product by means of a pulverizer, and classifying the pulverized product by means of a classifier to have the desired particle diameter.
  • a coloring agent such as a dye or a pigment
  • additives such as a charge control agent
  • release material a material with release properties
  • the release material there are limitations such that i) the material is not liquefied at the kneading temperature at which it is kneaded together with the resin, and ii) the release material must be contained in an amount of not more than about 5% by weight. Because of such limitations, there is a difficulty in improving the fixing performance of the toners produced by pulverization.
  • the release material is present not only in the interiors of toner particles but also on the surfaces of the toner particles.
  • an appropriate amount of low-molecular weight material with low melt viscosity must be added to the toner so that a sufficient releasability can be provided between a fixing roller of a fixing device and the image to be fixed.
  • the low-molecular weight material is also present on the surfaces of toner particles. This brings about a problem of blocking of the toner. It is difficult for the toner produced by pulverization to satisfy both the release properties and anti-blocking properties.
  • a low-molecular weight material highly capable of imparting releasability must be contained to improve the anti-offset properties, and at the same time, satisfying the anti-blocking properties and the transparency after fixing.
  • Fixing devices used in the heat-fixing method have hitherto employed a system in which an image is fixed while a transfer medium having an unfixed toner image on its surface is held between, and transported through, a fixing roller, kept at a given temperature, and a pressure roller having an elastic layer and brought into pressure contact with the fixing roller.
  • the unfixed toner on the transfer medium may adhere to the surface of the fixing roller that heats the toner and fuses it to the transfer medium, and this adhered toner is often transferred to the next transfer medium (i.e., an offset phenomenon).
  • an offset phenomenon occurs with greater frequency in full-color toner image fixation than in single-color toner fixation wherein the toner is merely softened and fixed under application of pressure.
  • a cross-linked resin component As a means for preventing the offset phenomenon, it is common to incorporate a cross-linked resin component into a toner. This method can be effective for imparting anti-offset properties, but may cause the lowering of heat fusion characteristics of the toner.
  • the plural kinds of color toners In order to reproduce a half tone in the multi- or full-color fixation process the plural kinds of color toners must be mixedly present on a transfer medium, must be melted in a good state, and it is preferable that the cross-linked resin component not be contained in the toner. For this reason, in a method of fixing color toners using a heat roller, it is common to prevent high-temperature offset by coating the heat roller with a release material such as silicone oil.
  • U.S. Pat. No. 3,578,797 proposes a method in which a toner image is heated to its melting point by a heating element, the toner image thereby melted is thereafter cooled into a relatively viscous state, where a transfer medium (a toner bearing medium) having the toner image is separated from a heating web in the state that the toner has a weakened adhesion, so that the toner image can be fixed without causing the offset.
  • a transfer medium a toner bearing medium
  • 3,578,797 also discloses a system in which the toner image is heated without bringing the toner image and transfer medium into pressure contact with the heating element, so that the transfer medium is not positively heated and hence, the toner can be melted using a smaller amount of energy than in other methods.
  • the toner image and transfer medium come into contact with the heating element without the pressure contact, the efficiency of thermal conduction is lowered and it takes a relatively long time for the heating and melting of the toner to occur.
  • the method disclosed in U.S. Pat. No. 3,578,797 must be further improved when full-color toner images are desired.
  • Japanese Patent Publication No. 51-29825 proposes that a pressure contact means is added to the fixing method of U.S. Pat. No. 3,578,797 so that the efficiency of thermal conduction can be improved and the toner can be heated and melted in a short time and yet in a satisfactory state.
  • This method makes it possible to sufficiently heat and melt the toner because of the pressure contact employed, and is particularly preferable in the color mixing in the formation of color toner images. Since, however, the pressure is applied at the time the toner is heated and melted, the adhesion between the heating element and the toner may become so strong that separation of the toner image transfer medium from the heating element becomes problematic even after the toner cools.
  • Teflon (a trade name of fluorine resins such as polytetrafluoroethylene) with a low surface energy is used on the surface of the heating element so that adhesion between the toner and the heating element can be decreased and the separation of the toner image transfer medium from the heating element can be improved.
  • An object of the present invention is to provide a heat-pressure fixing method that has eliminated the above problems.
  • Another object of the present invention is to provide a heat-pressure fixing method that can achieve a superior low-temperature fixing performance.
  • Still another object of the present invention is to provide a heat-pressure fixing method that can achieve superior anti-offset properties in high-temperature running.
  • a further object of the present invention is to provide a heat-pressure fixing method that may cause less winding of a transfer medium around a fixing roller.
  • a still further object of the present invention is to provide a heat-pressure fixing method that can achieve a superior running performance on a large number of copy sheets.
  • a still further object of the present invention is to provide a heat-pressure fixing method that can form a fixed image having a superior gloss.
  • the objects of the present invention can be achieved by a heat-pressure fixing method comprising the following steps.
  • Mw weight average molecular weight
  • said toner further contains tetrahydrofuran(THF)-soluble matter whose molecular weight distribution, as measured by gel permeation chromatography, has a weight average molecular weight (Mw) of from 10,000 to 500,000, a number average molecular weight (Mn) of from 1,000 to 100,000, Mw/Mn (value-A) of from 4 to 20, while Mw/Mn (value-B) of the THF-soluble matter having a molecular weight of not less than 1,500, is from 2 to 10.
  • Mw weight average molecular weight
  • a second step of fixing said toner image on the transfer medium by the use of a fixing means comprising a fixing roller and a pressure roller that are so provided as to be in mutual pressure contact and through which said transfer medium comes out in the direction inclined toward the pressure roller from the line perpendicular to the line connecting the center of the fixing roller and the center of the pressure roller.
  • the pressure applied between the fixing roller and the pressure roller is not less than 2 kg/cm 2 and the surface of said fixing roller is made of a material comprising a fluorine-containing material.
  • FIG. 1 is a schematic illustration of an example of the fixing device used in the present invention.
  • FIG. 2 is a view relating to a fixing device in which paper comes out in the direction inclined toward the pressure roller side.
  • FIG. 3 is a view relating to a fixing device in which paper comes out in the direction inclined toward the fixing roller side.
  • FIGS. 4 and 5 are views relating to GPC chromatograms of toners.
  • FIG. 6 is a schematic illustration of a full-color copying machine.
  • FIG. 7 is a view to illustrate the melting point of the wax used in the present invention.
  • FIG. 8 is a schematic illustration of a flow tester.
  • FIG. 9 shows a flow-out curve of a toner, measured by the flow tester.
  • the device used as a a fixing device is a heat-roller fixing device provided with a fixing roller and a pressure roller, wherein i) the surface of said fixing roller is made of a material comprising a fluorine-containing material, ii) when a blank sheet of paper is passed through the rollers, the sheet comes out in the direction inclined toward the pressure roller from the line perpendicular to the line connecting the center of the fixing roller and the center of the pressure roller, and also iii) the pressure applied between the fixing roller and the pressure roller is not less than 2 kg/cm 2 .
  • pressure roller side means to the side on which no toner image is borne of a transfer medium such as paper or OHP film. That is to say, for example, when a sheet of paper comes out in the direction inclined toward the pressure roller, the toner image heated by the fixing roller can be separated from the fixing roller at a greater angle.
  • the offset phenomenon is concerned with the agglomeration force acting between toner particles, the affinity of the toner particles for the fixing roller and the affinity of the toner particles for the transfer medium.
  • the pressure applied between the fixing roller and the pressure roller is controlled to be not less than 2 kg/cm 2 , and preferably not less than 3 kg/cm 2 .
  • a fixing pressure less than 2 kg/cm 2 may result in poor anti-offset properties. Some reasons therefor can be presumed. One reason is that when a low pressure is applied the wax enclosed in each toner particle cannot easily exude therefrom to the interface between the toner particle and the fixing roller. The other reason is that such a low pressure results in an insufficient deformation of toner particles to provide a weak agglomeration force between toner particles.
  • setting the fixing pressure to such a high degree can bring about a desirable improvement in high-temperature off-set phenomenon.
  • Setting the fixing pressure to such a high degree can also bring about an improvement in the surface smoothness of a fixed image obtained, thus giving a high image quality.
  • a toner image is fixed to a sheet for an overhead projector (OHP)
  • OHP overhead projector
  • the paper output direction(line n) is defined to be on the pressure roller side.
  • the blank sheet of paper used here has a weight of 60 g/m 2 to 85 g/m 2 , and is passed through the rollers in such a state that the direction of paper texture and the directions of roller shafts are parallel.
  • the surface temperature of the fixing roller is controlled to be 150° C. to 200° C.
  • the paper is passed at a speed of 85 mm/sec to 140 mm/sec.
  • the paper output direction is judged using a high-speed camera.
  • the paper output direction can be controlled to be on the pressure roller side, for example, in the following way:
  • the pressure roller is made to have a hardness higher than the hardness of the fixing roller.
  • the pressure roller can be made to have such a higher hardness by a method including a) a method in which an elastic material is made to have a higher hardness and b) a method in which an elastic material layer is made thin.
  • the fixing roller is made to have a larger diameter than the diameter of the pressure roller.
  • a heating device may be provided not only to the fixing roller but also to the pressure roller, so that the winding-jam of paper can be significantly reduced.
  • the fixing device in which such a method is employed may include a roller comprising as the fixing roller an elastic material comprised of a silicone rubber, which is of an RTV-type or LTV-type, and whose surface is made of a fluorine-containing material, preferably a fluorine resin.
  • the fixing roller used may have a double-layered structure comprising a combination of a silicone rubber and a fluorine rubber or a combination of a silicone rubber or fluorine rubber and a Teflon-coated material.
  • the fixing roller may have a triple-layered structure comprising a combination of a silicone rubber or fluorine rubber, a Teflon-coated material and a fluorine rubber.
  • the fixing roller is a roller comprising a mandrel and having provided thereon a coat-layer having a double-layered structure.
  • the double-layered structure comprises a lower layer comprising an elastic HTV silicone rubber and an upper layer comprising a PFA resin, or a roller having a coat-layer of an HTV silicone rubber layer as the lower layer and a fluorine resin-dispersed fluorine rubber layer as the upper layer, on which the fluorine resin is locally deposited by heat treatment.
  • the fluorine resin layer thus formed may preferably have a thickness of 5 ⁇ m to 100 ⁇ m, and preferably 10 ⁇ m to 60 ⁇ m.
  • the surface of the fixing roller should have a hardness (in the case of two layers, a hardness in total of the two layers) of 30° to 70°, and preferably 35° to 60°, as a rubber hardness (JIS-A).
  • the layer on the mandrel of the fixing roller should have a thickness of 0.5 mm to 5 mm, preferably 1.0 mm to 3.5 mm, and more preferably 1.0 mm to 3 mm.
  • the surface material of the pressure roller may preferably have a higher hardness than the surface layer of the fixing roller. Its surface may have a hardness of not less than 40°, and preferably not less than 50°.
  • a material therefor a silicone rubber material, a fluorine rubber material and a Teflon-coated material can be used.
  • the diameter of each roller cannot be made excessively large because of the demand for compact size copying machines. On the other hand, an excessively small roller diameter can not provide enough nip area between rollers to allow the toner to sufficiently melt, resulting in a poor color mixing performance or slower fixing speed in order to achieve a good color mixing performance.
  • it is suitable for the fixing roller and the pressure roller to each be 30 mm to 90 mm in diameter, and preferably 40 mm to 80 mm in diameter.
  • FIG. 1 schematically illustrates an example of a preferred fixing device.
  • a fixing roller 11 comprises a mandrel 11a provided in its interior with a heater 11b, an HTV silicone rubber layer 11c provided on the mandrel, and a tetrafluroethylene-perfluoroalkyl vinyl ether copolymer (PFA resin) layer 11d further provided thereon.
  • the pressure roller 12 comprises a mandrel 12a provided in its interior with a heater 12b, and a fluorine rubber layer 12c provided on the mandrel.
  • the paper output direction is on the pressure roller side as shown in FIG. 2.
  • a negatively chargeable toner is used as the toner.
  • the toner image has a negative triboelectricity and is electrostatically repulsed by the surface of the fixing roller comprising a fluorine-containing material.
  • the fixing method of the present invention can bring about a further improvement in the anti-offset properties and winding jam prevention.
  • the paper output direction tends to be upward. That is, the transfer medium having passed the nip portion comes out toward a fixing roller 13.
  • the toner is not only heated when the transfer medium passes the nip portion, but also when said toner is exposed to radiation heat from the fixing roller 13 even after the transfer medium has come out of the nip portion.
  • the paper emerges from the nip attached to the fixing roller until the paper contacts a separation claw, resulting in the toner being excessively melted by excess heat.
  • a fixed image may have an extremely high gloss, and also the offset phenomenon tends to occur.
  • the fixing method of the present invention can be greatly effective when multi-color toner images are fixed.
  • the wax with a weight average molecular weight (Mw) of from 500 to 1,500 may referably comprise a non-polar material and also have release properties.
  • Mw weight average molecular weight
  • it may preferably be paraffin wax.
  • the paraffin wax is enclosed inside of each toner particle.
  • the toner in which the paraffin wax is enclosed can be preferably prepared by suspension polymerization as described later.
  • the paraffin wax is liquefied at an environmental temperature when it has a lower melting point than the environmental temperature, and hence it may exude from the interior to the surface layer even when enclosed within toner particles and cause blocking in some instances.
  • the paraffin wax should have a melting point of 55° C. to 100° C., preferably from 60° C. to 100° C., and more preferably 65° C. to 80° C.
  • the paraffin wax should be contained in an amount of 10 parts by weight to 50 parts by weight, and preferably 15 parts by weight to 45 parts by weight, based on 100 parts by weight of a vinyl resin.
  • the wax is present in an amount less than 5 parts by weight, this may bring about a difficulty in imparting satisfactory release properties to the toner. If present in an amount more than 50 parts by weight, this situation makes it difficult for the paraffin wax to be well enclosed in toner particles, tending to cause blocking of the toner.
  • the melting point of the paraffin wax can be measured by the following method.
  • the melting point of paraffin wax is measured by differential scanning analysis using a differential scanning calorimeter (DSC).
  • a differential scanning calorimeter DSC-7 manufactured by Perkin Elmer Co., is used in the measurement.
  • a measuring sample is precisely weighed in an amount of 5 to 20 mg, and preferably 10
  • the sample is put in an aluminum pan, and, using an empty aluminum pan as a reference, the measurement is carried out in an environment of normal temperature and normal humidity, setting the measuring temperature within the range of 30° C. to 200° C. and raising the temperature at a rate of 10° C./min.
  • the temperature at which an endothermic peak corresponding to the main peak within the range of temperatures 30° C. to 160° C. is determined as the melting point of the paraffin wax in the present invention.
  • the surface of the fixing roller of the fixing device is made of a material comprising a fluorine-containing material.
  • the fluorine-containing material for the surface of the fixing roller is a material with a small surface energy and superior release properties. In order to make such a feature of the roller more effective, it is preferred to use the material that may give a contact angle with water of 80° to 110° to the surface of a pellet prepared by molding a toner.
  • a fixing roller having a silicone rubber surface layer coated with a silicone oil can be a roller having a superior anti-offset properties, but cannot necessarily bring about good results even when used in combination with the toner of the present invention, as compared with the fluorine type fixing roller.
  • the silicone rubber roller requires a higher running cost because of the consumption of silicone oil in large quantities.
  • the contact angle in the present invention can be measured in the following way.
  • the toner is formed into pellets using a tablet machine.
  • the molding surface should be mirror-finished and a sufficient pressure should be applied so that smooth surfaces can be obtained.
  • the contact angle of the surface of the resulting pellet and the water surface is measured using a contact angle meter (a CA-DS type, manufactured by Kyowa Kagaku K.K.).
  • the toner used in the present invention is obtained, for example, by the method as described below.
  • a wax e.g., paraffin wax
  • a coloring agent e.g., paraffin wax
  • a polymerization initiator e.g., a polymerization initiator
  • other additives are added to polymerizable monomers, and these are uniformly dissolved or dispersed using a dispersion machine, such as an ultrasonic dispersion machine or a homogenizer, to give a monomer composition.
  • This monomer composition is dispersed in an aqueous phase (i.e., a continuous phase) containing a suspension stabilizer using a usual stirring machine or a high-shear stirring machine such as a homomixer or a homogenizer.
  • the stirring speed and stirring time may preferably be controlled so that the droplets of the monomer composition have a size of the desired toner particles (usually a size of not more than 30 ⁇ m), and thereafter, the stirring may be carried out to the extent that the settling of particles is prevented and the state of dispersion can be maintained by the action of the dispersion stabilizer.
  • the polymerization may be carried out using a polymerization temperature of 40° C. or above, and usually a temperature of 50° C. to 90° C. In view of the need to control of the molecular weight distribution of the resin component, it is preferable to change the polymerization temperature during polymerization. After the reaction has been completed, the toner particles thus produced are washed and then collected by filtration, followed by drying.
  • water may preferably be used as a dispersion medium usually in an amount of 200 parts by weight to 3,000 parts by weight based on 100 parts by weight of monomers.
  • a wax having substantially no hydroxyl group, carboxyl group or ester group can be readily enclosed in the interior of each particle.
  • the polymerizable monomers that can be applied in the production of the toner used in the present invention may include vinyl monomers. They can be exemplified by styrene, styrene derivatives such as o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene and p-ethylstyrene, methacrylic esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate, acrylic esters such as
  • These monomers can be used alone or in the form of a mixture. Of the above monomers, it is preferred in view of the developing performance and durability of the toner to use styrene or a styrene derivative alone, or a combination of styrene and another monomer as polymerizable monomers.
  • the polymerization initiator used for polymerizing the monomers may include azo or diazo type polymerization initiators such as 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4 -dimethylvaleronitrile and other azobisisobutyrionitrile (AIBN); and peroxide-type polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorylbenzoylperoxide, and lauroyl peroxide. These polymerization initiators may preferably be used usually in an amount of about 0.5% by weight to about 5% by weight of the weight of the polymerizable monomers.
  • the polymerization initiator in order to prepare the toner of the present invention by the suspension polymerization, it is preferred, in view of the need to control the molecular weight characteristics of the resin component to use the polymerization initiator in a combination of two or more kinds. It is more preferable to use a combination of two polymerization initiators whose half-life at the reaction temperature of the initial stage of the polymerization are 100 minutes to 500 minutes and 1,000 minutes to 5,000 minutes, respectively.
  • a polar material such as a polymer having a polar group or a copolymer having a polar group.
  • the material used as the polar material contained in the monomer is a material having a polar group in the molecule and capable of causing a decrease in surface tension at the interface between water and the polymerizable monomer composition.
  • the above polar material used in the present invention may preferably be a slightly water-soluble material from the viewpoint of improving environment characteristics of the toner particles.
  • the "slightly water-soluble material” refers to a material with a solubility of not more than 1 g, and preferably a solubility of not more than 500 mg, and particularly preferably not more than 100 mg, in 100 ml of water.
  • a low-molecular compound or a polymeric compound can be used as the above polar material.
  • the latter polymeric compound is preferred.
  • a compound having a weight average molecular weight of from 5,000 to 500,00 as measured by GPC (gel permeation chromatography) may preferably be used in view of the advantages that it can readily dissolve or disperse in the polymerizable monomers and can also impart the durability to the toner.
  • anionic compounds as shown below are preferably used as this polar material.
  • They are compounds containing an anionic polar group as exemplified by a carboxyl group, a hydroxyl group, a dibasic acid group, a dibasic acid anhydride group, a sulfonic acid group, a sulfonate group or a phosphate group.
  • They may more specifically include polymers or copolymers of polar vinyl monomers as exemplified by unsaturated carboxylic acids such as acrylic acid or methacrylic acid, unsaturated dibasic acids, anhydrides of unsaturated dibasic acids, and acrylates or, methacrylates having a hydroxyl group; copolymers of any of these polar vinyl monomers and styrene, acrylate or methacrylate; and polyester resins.
  • unsaturated carboxylic acids such as acrylic acid or methacrylic acid, unsaturated dibasic acids, anhydrides of unsaturated dibasic acids, and acrylates or, methacrylates having a hydroxyl group
  • copolymers of any of these polar vinyl monomers and styrene, acrylate or methacrylate and polyester resins.
  • the polar material comprises the anionic polar polymer
  • it may preferably have an acid value and/or hydroxyl group value of 0.5 to 100, and preferably 1 to 30. It may preferably be added in an amount of 0.5 part by weight to 50 parts by weight, and more preferably 1 part by weight to 40 parts by weight, based on 100 parts by weight of the polymerizable monomers.
  • a polymer with an acid value and/or hydroxyl group value of less than 0.5 can be less effective for decreasing the surface tension.
  • a polymer with an acid value and/or hydroxyl group value of more than 100 is undesirable since it may bring about an excessively strong hydrophilicity.
  • the acid value refers to the number of milligrams of potassium hydroxide required for neutralizing carboxyl groups contained in 1 g of a sample.
  • the hydroxyl group value refers to the number of milligrams of potassium hydroxide required for neutralizing acetic acid combined with hydroxyl groups when 1 g of a sample is acetylated by the prescribed method.
  • polar materials should be added in an amount of 0.5 part by weight to 50 parts by weight, and preferably 0.5 part by weight to 50 parts by weight, based on 100 parts by weight of the polymerizable monomers. Addition of these polar materials in an amount less than 0.5 part by weight makes it difficult to obtain a sufficient quasi-capsule structure and therefore making it difficult for the wax to be well enclosed and resulting in a lowering of anti-blocking properties. Addition in an amount more than 50 parts by weight may result in a shortage of the amount of the polymerizable monomers, strongly tending to lower the characteristics required as a toner.
  • the polymerization may preferably be carried out by suspending the polymerizable monomer composition, in which any of the above polar materials has been added, in an aqueous phase of an aqueous medium in which a slightly water-soluble inorganic dispersant, that is soluble in a Br nsted acid such as hydrochloric acid, has been dissolved.
  • the polar material is attracted to the surface layers of the particles that form a toner, and hence gives a form like a shell.
  • the resulting particles each come to have a quasi-capsule structure.
  • the polar material with a relatively high molecular weight, attracted to the particle surface layers, imparts excellent properties to the toner, as exemplified by anti-blocking properties, developability, charge control properties and wear resistance.
  • slightly water-soluble inorganic dispersant that is soluble in a Br.0.nsted acid, it refers to an inorganic compound slightly soluble in water and also soluble in a Br.0.nsted acid. Stated more specifically, the water-soluble inorganic dispersant has a solubility of not less than 20 g in 100 ml of water.
  • the inorganic compound slightly soluble in water refers to a compound having a solubility of not more than 10 mg, and preferably not more than 5 mg, in 100 ml of neutral ion-exchanged water.
  • inorganic compound that is rendered neutral or alkaline in water
  • it can be exemplified by calcium phosphate, magnesium phosphate, calcium sulfate, magnesium carbonate, calcium carbonate, and Ca 3 (PO 4 ) 2 .Ca(OH) 2 .
  • Such inorganic compounds may preferably have a particle diameter of 2 ⁇ m or less, and more preferably 1 ⁇ m or less, as a primary particle.
  • the particle diameter in a dispersion medium of the slightly water-soluble inorganic dispersant described above can be measured using a Coulter counter.
  • a sample (the inorganic compound) is added so as to be in a concentration of 10%, and is subjected to ultrasonic dispersion according to a conventional method (36 kHz, 100 W, for 1 minute). Thereafter, the particle diameter is measured with a Coulter counter by a conventional method by the use of a 100 ⁇ m orifice.
  • the proportion of particles of 5.04 ⁇ m or larger in particle diameter is 5% by number, and it is more preferred that the proportion of particles of 3.17 ⁇ m or larger in particle diameter is 5% by number.
  • an inorganic dispersant a slightly water-soluble inorganic compound such as calcium phosphate can be prepared using sodium phosphate and calcium chloride in water, which may be used directly. This method is preferred in view of the advantage that an inorganic compound that is in the state of fine particles and has a good dispersibility can be readily obtained.
  • the powder of slightly water-soluble inorganic compound strongly agglomerates and the particle diameters in this agglomerated state are not uniform. Hence, when such a powder is used, its dispersion in water must be carefully carried out in many instances.
  • use of the method wherein the slightly water-soluble inorganic compound is formed in water as described above does not require such care and makes it possible to obtain a good dispersed state of the inorganic compound.
  • water-soluble neutral salts that are formed together with the slightly soluble compound when the slightly water-soluble compound is formed in water, have both the effect of preventing the monomers from being dissolved in water and the effect of increasing the specific gravity of the aqueous medium.
  • the pH of the dispersion medium containing the slightly water-soluble inorganic dispersant as described above is adjusted to preferably 7.1 to 11.0.
  • the dispersion medium may become so strongly alkaline that the monomer composition tends to have insufficient granulating properties.
  • the surface of the monomer composition may have an insufficient decrease in surface tension.
  • the pH may preferably be adjusted by adding to the dispersion medium containing the slightly water-soluble inorganic dispersant an alkaline water-soluble inorganic salt to give an aqueous dispersion medium having the capability of promoting the surface activity of the polar material.
  • the alkaline water-soluble inorganic salt used in such an instance may include Na 3 PO 4 , Na 2 CO 3 , NaOH and KOH.
  • the water-soluble inorganic salt may optionally be used in combination of two or more kinds.
  • a preferred combination thereof may include a combination of an anionic compound and a slightly water-soluble inorganic dispersant which can be neutral or alkaline in water. In such a combination, it is more preferred to adjust the pH by adding the alkaline water-soluble inorganic salt.
  • the slightly water-soluble inorganic dispersant may also optionally be used in combination of two or more kinds.
  • a medium having substantially no compatibility with the polymerizable monomers is used as the dispersion medium. It is preferred to use an aqueous dispersion medium.
  • a medium containing substantially no water-soluble surface active agent is used for the dispersion medium containing the slightly water-soluble inorganic dispersant.
  • the water-soluble surface active agent can be used in an amount not more than 0.001 part by weight based on 100 parts by weight of the inorganic dispersion stabilizer previously described. The use of a water-soluble surface active agent, however, is not necessary.
  • the above method is particularly preferred when the polymerization is carried out at a low temperature, thereby effecting suppressed decomposition of a polymerization initiator and thus increasing the polymer molecular weight.
  • the purpose of said initiator is to control the molecular weight distribution of the polymer, in view of the resultant cohesion attribute to the increasing viscosity during the prolonged polymerization process.
  • the polymerization temperature in such an instance may preferably be such a temperature that the half-life of the polymerization initiator comes to be 500 minutes or more, and more preferably 1,000 minutes or more.
  • the granulation of the monomer composition in the aqueous dispersion medium is carried out, for example, with a homomixer, homogenizer or the like having a high-speed rotary turbine and a stator.
  • the stirring speed and time may preferably be controlled so that the particle size of the monomer composition becomes 30 ⁇ m or less.
  • the number of revolution may preferably be set so that the turbine is rotated at a peripheral speed of 10 m/sec to 30 m/sec.
  • the granulation time which may preferably be 5 minutes to 60 minutes.
  • the liquid temperature may be controlled to make the viscosity of the monomer composition 1 cps to 1,000,000 cps, and preferably 10 cps to 100,000 cps.
  • This viscosity range thus enables the particle diameter of the monomer composition to be made 1 ⁇ m to 10 ⁇ m, resulting in a toner for development having a weight average particle diameter of 1 to 10 ⁇ m.
  • the temperature of the dispersion system should preferably be controlled at 20° C. to 80° C., and more preferably 40° C. to 70° C.
  • the liquid dispersion medium may preferably be present in amount of from 200 to 1,000 parts by weight based 100 parts by weight of the monomer composition.
  • the slightly water-soluble inorganic dispersant may preferably be used in an, amount of 1% to 20% by weight, and more preferably 1% to 10% by weight, based on the weight of the polymerizable monomer composition (at the time of granulation or at the initial stage of the polymerization).
  • the polymerization is carried out using a method in which it is confirmed that the particles of the monomer composition have a given particle size, and then the polymerization is allowed to proceed while controlling the liquid temperature (e.g., 55° C. to 70° C.) of the aqueous medium containing such particles.
  • the liquid temperature e.g. 55° C. to 70° C.
  • a method may be employed in which, by controlling the liquid temperature of the dispersion medium, the polymerization is allowed to proceed simultaneously with the granulation and dispersion process.
  • toner particles can be obtained by a conventional post treatment.
  • a Br.0.nsted acid is added to a system containing the polymer particles thus produced, and the slightly water-soluble inorganic dispersant is removed by a suitable means such as filtration, decantation or centrifugal separation to collect the polymer particles which are then dried to give a toner.
  • the Br.0.nsted acid-soluble, slightly water-soluble inorganic dispersant used in the present invention can be readily removed from toner particle surfaces by the above acid treatment.
  • the toner from which the dispersant has been removed there is substantially no ill influence that makes the toner particle surfaces hydrophilic (which is due to residual dispersant), and thus a good toner development performance can be obtained.
  • the wax having a weight average molecular weight (Mw) of 500 to 1,500 and a melting point of 55° C. to 100° C. can be well enclosed in the particle. It is also important to select conditions for its production so that the toner produced by suspension polymerization of the polymerizable monomer composition can have such molecular weight distribution of total THF-soluble matter contained therein, that the weight average molecular weight (Mw) is from 10,000 to 500,000, and preferably 15,000 to 200,000, a number average molecular weight (Mn) from 1,000 to 100,000, and preferably 2,000 to 30,000.
  • Mw/Mn (value-A) is from 4 to 20, and preferably 5 to 15, as well as Mw/Mn(value-B) for a THF-soluble matter having a molecular weight of not less than 1,500, is from 2 to 10, and preferably 2.5 to 8. These values are determined by gel permeation chromatography. In view of the offset prevention, the value-A of Mw/Mn may more preferably be larger than the value-B by 2 or more.
  • FIG. 4 shows a chromatogram obtained by GPC of the THF-soluble matter of a toner obtained in Example 1 described later.
  • the weight average molecular weight (Mw) is 56,000
  • the number average molecular weight (Mn) is 6,000
  • the value-A of Mw/Mn is 9.3.
  • FIG. 5 shows a chromatogram obtained when the region corresponding to a molecular weight of not more than 1,500 is deleted from the chromatogram shown in FIG. 4 and data are calculated.
  • the weight average molecular weight (Mw) is 62,000
  • the number average molecular weight (Mn) is 17,000
  • the value-B of Mw/Mn is 3.6. Therefore the value-A of Mw/Mn is larger than the value-B by 5.7.
  • the toner of the present invention becomes suitable for the heat-pressure fixing when such conditions are met.
  • the wax contained in the polymerizable monomer composition is dissolved in the polymerizable monomers, and further that the polymerization is carried out at a temperature not higher than the melting point of the wax. Additionally, the polymerization process is so controlled that the the wax is made to be gradually deposited with progress of the polymerization process and thus is enclosed in the center of each toner particle.
  • the molecular weight distribution of the toner of the present invention is measured, for example, in the following way.
  • 150 C ALC/GPC manufactured by Waters Co, is used to measure the molecular weight under the following conditions:
  • the retention time of the standard sample is read to prepare a calibration curve, and the molecular weight of the sample is calculated from the calibration curve.
  • the coloring agent contained in the toner of the present invention may include dyes or pigments.
  • it may include phthalocyanine pigments, azo pigments, quinacridone pigments, xanthene dyes, and carbon black.
  • the coloring agent should be used in an amount of from 0.5 to 40 parts by weight, and preferably 1 to 25 parts by weight, based on 100 parts by weight of the resin component.
  • a charge control material may optionally be added to the toner.
  • charge control materials such as a metal complex salt of an azine dye or monoazo dye containing an alkyl group having 2 to 16 carbon atoms, and a metal complex salt of salicylic acid or dialkylsalicylic acid.
  • the azine dye may preferably be used in such a very small amount (e.g., not more than 0.3% by weight, and more preferably 0.05% by weight to 0.2% by weight) so as to not damage color tones of color toners such as a cyan toner, a magenta toner and a yellow toner.
  • a very small amount e.g., not more than 0.3% by weight, and more preferably 0.05% by weight to 0.2% by weight
  • the agglomeration of the toner of the present invention may preferably be not more than 40%, and preferably 1% to 30%, even after it has been left at a temperature of 50° C. for 48 hours.
  • the degree of agglomeration after leaving at 50° C. for 48 hours is regarded as one of the barometers of the anti-blocking properties of toners and the wax enclosure in the toner particle.
  • the toner agglomerates into a mass, resulting in a large value for the degree of agglomeration.
  • the degree of agglomeration of the toner or a toner mixed with an additive such as hydrophobic colloidal silica can be measured by the following method.
  • a sample (a toner or a toner mixed with an additive such as hydrophobic colloidal silica is left in an environment of 23° C. for about 12 hours for measurement. Measurement is made in an environment of a temperature of 23° C. and a humidity of 60% RH.
  • Powder Tester (trade name; manufactured by Hosokawa Micron Corporation) is used.
  • 200 mesh, 100 mesh and 60 mesh sieves are overlaid on a vibrating pedestal in this order from the bottom according to the mesh size so that the 60 mesh sieve is uppermost.
  • the input voltage applied to the vibrating pedestal is set to 21.7 V, and the vibrational amplitude of the vibrating pedestal is so adjusted as to be within the range of 60 ⁇ to 90 ⁇ (rheostat gauge: about 2.5), and the sieves are vibrated for about 15 seconds.
  • the weight of the sample that remained on each sieve is measured to calculate the degree of agglomeration according to the following expression: ##EQU1##
  • a fluidity improver may be added to the external surfaces of the color toner particles.
  • the fluidity improver may include fine colloidal silica powder, hydrophobic fine colloidal silica powder, fine titanium oxide powder, hyrophobic fine titanium oxide powder, fatty acid metal, salt powder, and fine Teflon powder.
  • the toner of the present invention may preferably have a flow-out point at 75° C. to 95° C. in view of color mixing performance required for a full-color image fixation.
  • the melt behavior of the toner used in the present invention can be measured using an overhead-type flow tester as illustrated in FIG. 8 (Shimadzu Flow Tester CFT-500 Type).
  • a sample 83 molded by a pressure molder is extruded from a nozzle 84 of 1 mm in diameter and 1 mm in length under application of a load of 20 kgf using a plunger 1 under the temperatures elevation at a rate of 5.0° C./min and thus the distance of the plunger fall is measured.
  • the temperature at which the sample begins to flow out is regarded as the flow-out temperature.
  • the toner obtained by the method described above can be applied to dry electrostatic image development.
  • dry electrostatic image development For example, it can be applied to two-component development such as cascade development, magnetic brush development, micro-toning development and two-component AC bias development; one-component development making use of magnetic toners, such as conductive one-component development, insulating one-component development, and jumping development; powder cloud development and fur brush development; non-magnetic magnetic one-component development in which a toner is held on a toner carrying member by the action of an electrostatic force to be transported to a developing zone and used for development; and electric field curtain development in which a toner is transported to a developing zone by the electric field curtain method and used for development.
  • the toner obtained by the method described above can be particularly useful in development processes requiring a sharp particle size distribution, making use of a small-diameter toner with a weight average particle diameter (d4) of about 2 ⁇ m to 8.5 ⁇ m.
  • a fluidity improver may preferably be used by its mixture in toner particles.
  • the fluidity improver can be exemplified by fine colloidal silica powder, hydrophobic fine colloidal silica powder, fine fatty acid metal salt powder, fine Teflon powder, fine titanium oxide powder, and hydrophobic fine titanium oxide powder.
  • the particle size distribution of toners can be measured by various methods. In the present invention, it is measured using a Coulter counter.
  • a Coulter counter Type-II (manufactured by Coulter Electronics, Inc.) is used as a measuring device.
  • An interface manufactured by Nikkaki
  • a personal computer CX-I manufactured by Canon Inc.
  • an electrolytic solution an aqueous 1% NaCl solution is prepared using first-grade sodium chloride.
  • ISOTON-II (trade name; available from Coulter Scientific Japan Ltd.) can be used.
  • Measurement is carried out by adding as a dispersant 0.1 to 5 ml of a surface active agent (preferably an alkylbenzene sulfonate) to 100 ml to 150 ml of the above aqueous electrolytic solution, and further adding 2 to 20 mg of a sample to be measured.
  • a surface active agent preferably an alkylbenzene sulfonate
  • the electrolytic solution in which the sample has been suspended is subjected to dispersion for 1 to 3 minutes in an ultrasonic dispersion machine.
  • the 2 ⁇ to 40 ⁇ particle size distribution is measured on the basis of the number distribution using the above Coulter counter Type TA-II, with an 100 ⁇ aperture, and then the values according to the present invention are determined.
  • the present invention can be more effective for the case of a multi-color image.
  • An example of a method of obtaining the multi-color image will be described with reference to FIG. 6.
  • a photosensitive drum 32 is rotated in the direction of an arrow shown in FIG. 6, and a photosensitive layer formed on the drum 32 is uniformly charged by means of a primary corona assembly 33. Then, the photosensitive layer is image wise exposed to the modulated laser light E corresponding with a yellow image of an original, so that an electrostatic latent image of the yellow image is formed on the photosensitive drum 32.
  • the electrostatic latent image of this yellow image is developed by means of a yellow developer assembly 34Y previously set to a developing position with the rotation of a rotator 34 of a developing device III.
  • a transfer medium (not shown) transported from a paper feed cassette 101 or 102 through a paper feed guide 24a, paper feed roller 107 and a paper feed guide 24b is held by a gripper at a given timing, and electrostatically wound to a transfer drum 28 by means of a contacting roller 27 and an electrode opposingly provided thereto.
  • the transfer drum 28 is rotated in the direction shown by an arrow in FIG. 6, in synchronization with the photosensitive drum 32.
  • a visible image formed as a result of the development by the yellow developer assembly 34Y is transferred by means of a transfer corona assembly 29 where the peripheral surface of the photosensitive drum 32 and the peripheral surface of the transfer drum 28 come in contact with each other.
  • the transfer drum 28 continues to rotate preparation for the transfer of a next color (in the case of FIG. 6, magenta).
  • the photosensitive drum 32 is charge-eliminated by means of a residual charge eliminator 30 and cleaned by a cleaning means 31. Thereafter, it is again charged by means of the primary corona assembly 33, and then image-wise exposed as before, according to the next (e.g. magenta) image signals.
  • the developing device III is rotated while an electrostatic latent image according to the magenta image signals is formed on the photosensitive drum 32 as a result of the above image-wise exposure, so that a magenta developer assembly 34 M is set to its developing position and the magenta development is carried out. Subsequently, the processes described above are also applied to cyan color development and black color development, respectively.
  • the four-color visible image (toner image) formed on the transfer medium is charge-eliminated by means of corona assemblies 22 and 23.
  • the transfer medium is released from the grip of the gripper 26 and at the same time separated from the transfer drum 28 by means of a separating claw 40. It is then delivered through a delivery belt means 25 to an image fixing device provided with a fixing roll 11 and a pressure roll 12, where the image is color-mixed and fixed by the action of heat and pressure.
  • the transfer medium having the image thus fixed comes out to an output-paper tray 41.
  • part(s) refers to “part(s) by weight” (abbreviated to “pbw” in Tables).
  • aqueous dispersion medium containing fine calcium phosphate particles of 1 ⁇ m or less in particle diameter.
  • the pH of this aqueous dispersion medium was about 10.
  • the polymerizable monomer composition thus prepared kept at a temperature of 60° C., was poured, followed by stirring for 20 minutes in a nitrogen atmosphere at 60° C., using a TK type homomixer and with stirring blade revolution number of 10,000 rpm so that the polymerizable monomer composition was granulated in the aqueous dispersion medium. After the granulation was completed, the the mixture was stirred at 60° C. for 3 hours using a stirring machine (60 rpm) having paddle stirring blades, in place of the TK type homomixer, to allow the polymerization to proceed. Then the temperature of the mixture was raised to 80° C., the polymerization was further allowed to proceed with stirring for 10 hours.
  • a stirring machine 60 rpm
  • the yellow toner-A obtained was measured using a Coulter counter to determine that it had a weight average particle diameter (d4) of 8 ⁇ m and also had a sharp particle size distribution.
  • the flow-out point of this yellow toner-A measured by a flow tester was 76° C.
  • Mw weight average molecular weight
  • Mn number average molecular weight
  • Mw/Mn(value-A) was 9.3.
  • 900 parts of a resin-coated magnetic ferrite carrier (average particle diameter: 45 ⁇ m) and 100 parts of the yellow toner were blended to prepare a two-component developer.
  • the toner had negative triboelectric charges after the two-component developer had been shaken in a container.
  • the two-component developer thus prepared was fed to a modified machine of the full-color copier (CLC-1; manufactured by Canon Inc.) as schematically illustrated in FIG. 6, with successive supplement of the yellow toner-A, having hydrophobic fine colloidal silica powder on the particle surfaces, to carry out image reproduction tests and heat-roller fixing tests.
  • CLC-1 full-color copier
  • the fixing roller of the fixing test device was a roller of 40 mm in diameter, comprising a mandrel made of aluminum with a diameter of about 34 mm, provided with a heater in its interior, a 2 mm thick HTV silicone rubber layer formed on the surface of the mandrel, and a 30 ⁇ m thick PFA resin (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) layer on the rubber layer.
  • the surface of the fixing roller had a hardness of 45°.
  • the a pressure roller of the fixing device was roller of 40 mm in diameter, comprising a mandrel made of aluminum with a diameter of about 38 mm, with a heater provided in its interior, and an 1 mm thick fluorine rubber layer around the mandrel.
  • the surface of the pressure roller had a hardness of 55°.
  • the paper output direction was inclined toward the pressure roller as shown in FIG. 2.
  • the fixing tests were carried out on plain paper under the following conditions: The pressure between the rollers was controlled to be 3 kg/cm 2 , the fixing process speed was set to be 90 mm/sec, and the temperature was controllable within the temperature range of 100° C. to 200° C. at intervals of 5° C.
  • a fixed image obtained was rubbed with lens cleaning paper "DUSPER" (trade name; available from OZU Paper Co., Ltd.) under application of a load of 50 g/cm 2 , and the temperature at which the image density reduction after the rubbing comes to be 5% or less is regarded as a fixing start temperature. Offset resistance was evaluated on the basis of observations of fixed images.
  • Toner images were also fixed on OHP sheets at a process speed of 20 mm/sec at 150° C., and transmission spectrum of each sheet was measured with a spectrophotometer U-3400 (manufactured by Hitachi Ltd.) to evaluate the transparency of the yellow toner image.
  • a cyan toner-B was prepared by suspension polymerization in the same manner as in Example 1 except for using the above materials. Also in the same manner as in Example 1, the cyan toner-B obtained and the negatively chargeable hydrophobic fine colloidal silica powder were mixed, and the resulting mixture was then blended with a resin-coated magnetic ferrite carrier. A two-component developer was thus prepared.
  • a magenta toner-C was prepared by suspension polymerization in the same manner as in Example 1 except for using the above materials. Also in the same manner as in Example 1, the magenta toner-C obtained and the negatively chargeable hydrophobic fine colloidal silica powder were mixed, and the resulting mixture was then blended with the resin-coated magnetic ferrite carrier. A two-component developer was thus prepared.
  • a black toner-D was prepared by suspension polymerization in the same manner as in Example 1 except for using the above materials. Also in the same manner as in Example 1, the black toner-D obtained and the negatively chargeable hydrophobic fine colloidal silica powder were mixed, and the resulting mixture was then blended with the resin-coated magnetic ferrite carrier. A two-component developer was thus prepared.
  • a yellow toner-E was prepared in the same manner as in Example 1 except that the amount of the paraffin wax was changed to 95 parts. Also in the same manner as in Example 1, the yellow toner-E obtained and the negatively chargeable hydrophobic fine colloidal silica powder were mixed, and the resulting mixture was then blended with the resin-coated magnetic ferrite carrier. A two-component developer was thus prepared.
  • a yellow toner-F was prepared in the same manner as in Example 1 except that the amount of the paraffin wax was changed to 22 parts. Also in the same manner as in Example 1, the yellow toner-F obtained and the negatively chargeable hydrophobic fine colloidal silica powder were mixed, and the resulting mixture was then blended with the resin-coated magnetic ferrite carrier. A two-component developer was thus prepared.
  • a yellow toner-G was prepared in the same manner as in Example 1 except for using paraffin wax with a melting point of 60° C. Also in the same manner as in Example 1, the yellow toner-G obtained and the negatively chargeable hydrophobic fine colloidal silica powder were mixed, and the resulting mixture was then blended with the resin-coated magnetic ferrite carrier. A two-component developer was thus prepared.
  • a yellow toner-H was prepared in the same manner as in Example 1 except for using paraffin wax with a melting point of 100° C. Also in the same manner as in Example 1, the yellow toner-H obtained and the negatively chargeable hydrophobic fine colloidal silica powder were mixed, and the resulting mixture was then blended with the resin-coated magnetic ferrite carrier. A two-component developer was thus prepared.
  • a yellow toner-I was prepared by suspension polymerization in the same manner as in Example 1 except for using the above materials. Also in the same manner as in Example 1, the yellow toner-I obtained and the negatively chargeable hydrophobic fine colloidal silica powder were mixed, and the resulting mixture was then blended with the resin-coated magnetic ferrite carrier. A two-component developer was thus prepared.
  • Example 2 Toner image fixing tests were carried out in the same manner as in Example 1 except that the pressure between the fixing roller and the pressure roller was changed to 5 kg/cm 2 . The same good results as in Example 1 were obtained.
  • Toner images were formed using the two-component developer having the yellow toner-A prepared in Example 1, the two-component developer having the cyan toner-B prepared in Example 2 and the two-component developer having the magenta toner-C prepared in Example 3, and also using the modified machine of the copier shown in FIG. 6. Fixation was carried out in the same manner as in Example 1 to form a full-color image fixation. In the fixing for the full-color image, the same good results as in Example 1 were obtained.
  • Example 2 Toner image fixing tests were carried out in the same manner as in Example 1 except that the fixing roller is provided with a PTFE layer instead of a PFA layer. The same good results as in Example 1 were obtained.
  • a yellow toner-L was prepared by suspension polymerization in the same manner as in Example 1 except for using the above materials. Also in the same manner as in Example 1, the yellow toner-L obtained and the negatively chargeable hydrophobic fine colloidal silica powder were mixed, and the resulting mixture was then blended with the resin-coated magnetic ferrite carrier. A two-component developer was thus prepared.
  • the fixing roller of Comparative Example 1 had a fluorine rubber/Teflon coat (tetrafluoroethylene resin, PTFE) double-layered type construction with a surface hardness of 70°, a layer thickness of 1.0 mm and a roller diameter of 40 mm.
  • the pressure roller had a silicone rubber (HTV) single-layer with a surface hardness of 55°, a layer thickness of 5.0 mm, and a roller diameter of 40 mm.
  • the fixing roller and the pressure roller were in contact at a pressure of 3 kg/cm 2 . Heating devices were fitted in both the fixing roller and the pressure roller. In a blank-paper feeding test using this fixing device, the paper output direction was inclined toward the fixing roller.
  • the fixing roller had a silicone rubber double-layer (RTV/HTV) with a rubber layer thickness of 1 mm, a surface hardness of 55°, and a roller diameter of 40 mm, and the pressure roller a roller of a silicone rubber layer with a surface hardness of 45°, a layer thickness of 3 mm, and a roller diameter of 40 mm.
  • the fixing roller and the pressure roller were in contact at a pressure of 3 kg/cm 2 . Heating devices were fitted in both the fixing roller and the pressure roller. In a blank-paper feeding test using this fixing device, the paper output direction was inclined toward the fixing roller.
  • a yellow toner-M was prepared by suspension polymerization in the same manner as in Example 1 except for using the above materials. Also in the same manner as in Example 1, the yellow toner-M obtained and the negatively chargeable hydrophobic fine colloidal silica powder were mixed, and the resulting mixture was then blended with the resin-coated magnetic ferrite carrier. A two-component developer was thus prepared.
  • a yellow toner-N was prepared by suspension polymerization in the same manner as in Example 1 except for using the above materials. Also in the same manner as in Example 1, the yellow toner-N obtained and the negatively chargeable hydrophobic fine colloidal silica powder were mixed, and the resulting mixture was then blended with the resin-coated magnetic ferrite carrier. A two-component developer was thus prepared.
  • a yellow toner-O was prepared in the same manner as in Example 1 except for using a wax with a molecular weight of 500 and a melting point of 50° C., and then 100 parts of the yellow toner-O obtained and 0.5 part of a hydrophobic fine colloidal silica powder were mixed to prepare a yellow toner.
  • This yellow toner showed a degree of agglomeration of 16.1% in an environment of a temperature of 23° C. and a humidity of 60% RH, and a degree of agglomeration of 55.4% after it had been left at 50° C. for 48 hours.
  • This toner was inferior in blocking resistance compared with that of Example 1.
  • a yellow toner-P was prepared in the same manner as in Example 1 except for using a wax with the molecular weight of 2,000 and a melting point of 120° C.
  • the toner thus obtained had a broader particle size distribution than the toner of Example 1, and showed a poor development performance.
  • the fixing roller of Comparative Example 11 had a silicone rubber double-layer (RTV/HTV) with a rubber layer thickness of 3 mm, a surface hardness of 45°, and a roller diameter of 40 mm, and the pressure roller had a silicone rubber layer with a surface hardness of 55°, a layer thickness of 1 mm, and a roller diameter of 40 mm.
  • the fixing roller and the pressure roller were in contact at a pressure of 3 kg/cm 2 . Heating devices were fitted in both the fixing roller and the pressure roller. In a blank-paper feeding test using this fixing device, the paper output direction was inclined toward the pressure roller.
  • Image fixing tests were carried out in the same manner as in Example 1 except that the fixing roller and the pressure roller were brought in contact at a pressure of 1 kg/cm 2 . Test results are shown in Table 4.

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Cited By (14)

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US5619315A (en) * 1993-12-29 1997-04-08 Fuji Xerox Co., Ltd. Fixing apparatus using a coated elastic member for use in an image forming apparatus
US5747213A (en) * 1995-05-31 1998-05-05 Canon Kabushiki Kaisha Image forming method and heat fixing method using a toner including a wax
US5802440A (en) * 1995-06-30 1998-09-01 Canon Kabushiki Kaisha Cleaning apparatus for cleaning heat fixing member, heat fixing method and image forming method
US6032017A (en) * 1999-04-09 2000-02-29 Hewlett-Packard Company Fixing device using an adjustable heater to reduce contamination on media
US6294302B1 (en) * 1999-03-01 2001-09-25 Fuji Xerox Co., Ltd. Toner for developing static image, developer for developing static image, and image forming method
US6377777B1 (en) * 1999-02-19 2002-04-23 Canon Kabushiki Kaisha Fluorine-containing resin-coated pressure roller and heat-fixing device
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US6793216B2 (en) 2001-09-26 2004-09-21 Canon Kabushiki Kaisha Sheet material conveying device and image forming apparatus provided with such device
US20040229150A1 (en) * 2003-02-28 2004-11-18 Seiko Epson Corporation Toner
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US5619315A (en) * 1993-12-29 1997-04-08 Fuji Xerox Co., Ltd. Fixing apparatus using a coated elastic member for use in an image forming apparatus
US5747213A (en) * 1995-05-31 1998-05-05 Canon Kabushiki Kaisha Image forming method and heat fixing method using a toner including a wax
US5802440A (en) * 1995-06-30 1998-09-01 Canon Kabushiki Kaisha Cleaning apparatus for cleaning heat fixing member, heat fixing method and image forming method
US6377777B1 (en) * 1999-02-19 2002-04-23 Canon Kabushiki Kaisha Fluorine-containing resin-coated pressure roller and heat-fixing device
US6294302B1 (en) * 1999-03-01 2001-09-25 Fuji Xerox Co., Ltd. Toner for developing static image, developer for developing static image, and image forming method
US6032017A (en) * 1999-04-09 2000-02-29 Hewlett-Packard Company Fixing device using an adjustable heater to reduce contamination on media
US6473576B1 (en) 1999-05-31 2002-10-29 Canon Kabushiki Kaisha Image forming apparatus with sheet feeding device having sheet supporting portion
US6475686B2 (en) * 2000-07-28 2002-11-05 Canon Kabushiki Kaisha Fixing method
US6704526B2 (en) 2001-03-28 2004-03-09 Canon Kabushiki Kaisha Image heating apparatus adapted for cleaning of speed detection mark
US6945528B2 (en) 2001-05-10 2005-09-20 Canon Kabushiki Kaisha Sheet feeding apparatus and image forming apparatus
US6793216B2 (en) 2001-09-26 2004-09-21 Canon Kabushiki Kaisha Sheet material conveying device and image forming apparatus provided with such device
US20040229150A1 (en) * 2003-02-28 2004-11-18 Seiko Epson Corporation Toner
US8382099B2 (en) 2010-07-22 2013-02-26 Canon Kabushiki Kaisha Sheet conveying apparatus and image forming apparatus
US8919771B2 (en) 2010-07-22 2014-12-30 Canon Kabushiki Kaisha Sheet conveying apparatus and image forming apparatus
US20140323673A1 (en) * 2013-04-26 2014-10-30 Canon Kabushiki Kaisha Method for producing resin composition and resin composition
US9388264B2 (en) * 2013-04-26 2016-07-12 Canon Kabushiki Kaisha Method for producing resin composition and resin composition

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EP0470479A1 (en) 1992-02-12
DE69126572T2 (de) 1998-01-15
HK1001068A1 (en) 1998-05-22
CA2048036A1 (en) 1992-02-01
JPH04356057A (ja) 1992-12-09
DE69126572D1 (de) 1997-07-24
JP3029144B2 (ja) 2000-04-04
EP0470479B1 (en) 1997-06-18
CA2048036C (en) 1994-10-04

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